import java.util.ArrayList;

public class AVLTree<K extends Comparable<K>,V> implements Map<K,V>{

    private class Node{
        private K key;
        private V value;
        private Node left,right;
        public int height;

        public Node(K key,V value){
            this.key = key;
            this.value = value;
            this.left = null;
            this.right = null;
            this.height = 1;
        }
    }

    private Node root;
    private int size;

    public AVLTree(){
        root = null;
        size = 0;
    }

    /**
     * 向二分搜索树中添加新的元素(key, value)
     * @param key
     * @param value
     */
    @Override
    public void add(K key, V value) {
        root = add(root,key,value);
    }

    /**
     * 向以node为根的二分搜索树中插入元素(key, value)，递归算法
     * 返回插入新节点后二分搜索树的根
     * @param node
     * @param key
     * @param value
     * @return
     */
    private Node add(Node node,K key,V value){
        if(node == null){
            size++;
            return new Node(key,value);
        }
        if(node.key.equals(key))
            node.value = value;
        else if(key.compareTo(node.key) < 0)
            node.left = add(node.left,key,value);
        else //  key.compareTo(node.key) > 0
            node.right = add(node.right,key,value);

        //更新height
        node.height = Math.max(getHeight(node.left),getHeight(node.right)) + 1;

        int balanceFactor = Math.abs(getBalanceFactor(node));
        if(Math.abs(getBalanceFactor(node)) > 1){
            //TODO
            System.out.println("unbalances : "+balanceFactor);
        }
        return node;
    }

    /**
     * 获得节点node的高度
     * @param node
     * @return
     */
    private int getHeight(Node node){
        if(node == null)
            return 0;
        return node.height;
    }

    /**
     * 获得节点node的平衡因子
     * @param node
     * @return
     */
    private int getBalanceFactor(Node node){
        if(node == null)
            return 0;
        return getHeight(node.left) - getHeight(node.right);
    }

    /**
     *从二分搜索树中删除键为key的节点
     * @param key
     * @return
     */
    @Override
    public V remove(K key) {
        Node node = getNode(root,key);
        if(node != null){
            root = remove(root,key);
            return node.value;
        }
        return null;
    }

    /**
     * 向以node为根的二分搜索树中删除元素key，递归算法
     * 返回删除节点后二分搜索树的根
     * @param node
     * @param key
     * @return
     */
    private Node remove(Node node,K key){
        if(node == null)
            return null;
        if(key.compareTo(node.key) < 0){
            node.left = remove(node.left,key);
            return node;
        }else if(key.compareTo(node.key) > 0){
            node.right = remove(node.right,key);
            return node;
        }
        else {//key.equals(node.key)
                // 待删除节点左子树为空的情况
            if(node.left == null){
                Node rightNode = node.right;
                node.right = null;
                size --;
                return rightNode;
                // 待删除节点右子树为空的情况
            }else if(node.right == null){
                Node leftNode = node.left;
                node.left = null;
                size--;
                return leftNode;
            }else{
                // 待删除节点左右子树均不为空的情况

                // 找到比待删除节点大的最小节点, 即待删除节点右子树的最小节点
                // 用这个节点顶替待删除节点的位置
                Node successor = minimum(node.right);
                successor.left = node.left;
                successor.right = removeMin(node.right);
                node.left = node.right = null;
                return successor;
            }
        }
    }


    /**
     * 返回以node为根的二分搜索树的最小值所在的节点
     * @param node
     * @return
     */
    private Node minimum(Node node){
        if(node.left == null)
            return node;
        return minimum(node.left);
    }

    /**
     * 删除掉以node为根的二分搜索树中的最小节点
     * 返回删除节点后新的二分搜索树的根
     * @param node
     * @return
     */
    private Node removeMin(Node node){

        if(node.left == null){
            Node rightNode = node.right;
            node.right = null;
            size --;
            return rightNode;
        }

        node.left = removeMin(node.left);
        return node;
    }

    @Override
    public boolean contains(K key) {
        return getNode(root,key) != null;
    }

    /**
     * 返回以node为根节点的二分搜索树中，key所在的节点
     * @param node
     * @param key
     * @return
     */
    private Node getNode(Node node,K key){
        if(node == null)
            return null;
        if(key.equals(node.key))
            return node;
        else if(key.compareTo(node.key) < 0)
            return getNode(node.left,key);
        else
            //key.compareTo(node.key) > 0
            return getNode(node.right,key);
    }

    @Override
    public V get(K key) {
        Node node = getNode(root,key);
        return node == null?null:node.value;
    }

    @Override
    public void set(K key, V newValue) {
        Node node = getNode(root,key);
        if(node == null)
            throw new IllegalArgumentException(key+" doesn't exist!");
        node.value = newValue;
    }

    @Override
    public int getSize() {
        return this.size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    public static void main(String[] args) {
        System.out.println("Pride and Prejudice");

        ArrayList<String> words = new ArrayList<>();
        if(FileOperation.readFile("pride-and-prejudice.txt", words)) {

            AVLTree<String, Integer> map = new AVLTree<>();
            for (String word : words) {
                if (map.contains(word))
                    map.set(word, map.get(word) + 1);
                else
                    map.add(word, 1);
            }
            System.out.println("Total words: " + words.size());
            System.out.println("Total different words: " + map.getSize());
            System.out.println("Frequency of PRIDE: " + map.get("pride"));
            System.out.println("Frequency of PREJUDICE: " + map.get("prejudice"));
        }

        System.out.println();
    }

}
